Defining the propertyvalue construct.

• §1. Definition
• §2. Instructions
• §4. Creating from textual Inter syntax
• §5. Writing to textual Inter syntax
• §6. Access functions

§1. Definition. For what this does and why it is used, see Textual Inter (in inter).

void PropertyValueInstruction::define_construct?Usage of PropertyValueInstruction::define_construct:
Inter Constructs - §15(void) {
    inter_construct *IC = InterInstruction::create_construct(PROPERTYVALUE_IST, I"propertyvalue");
    InterInstruction::specify_syntax(IC, I"propertyvalue IDENTIFIER of IDENTIFIER = TOKENS");
    InterInstruction::data_extent_always(IC, 4);
    InterInstruction::permit(IC, INSIDE_PLAIN_PACKAGE_ICUP);
    METHOD_ADD(IC, CONSTRUCT_READ_MTID, PropertyValueInstruction::read);
    METHOD_ADD(IC, CONSTRUCT_TRANSPOSE_MTID, PropertyValueInstruction::transpose);
    METHOD_ADD(IC, CONSTRUCT_VERIFY_MTID, PropertyValueInstruction::verify);
    METHOD_ADD(IC, CONSTRUCT_XREF_MTID, PropertyValueInstruction::xref);
    METHOD_ADD(IC, CONSTRUCT_WRITE_MTID, PropertyValueInstruction::write);
}

§2. Instructions. In bytecode, the frame of a propertyvalue instruction is laid out with the compulsory words — see Inter Nodes — followed by:

define PROP_PVAL_IFLD  (DATA_IFLD + 0)
define OWNER_PVAL_IFLD (DATA_IFLD + 1)
define VAL1_PVAL_IFLD  (DATA_IFLD + 2)
define VAL2_PVAL_IFLD  (DATA_IFLD + 3)

inter_error_message *PropertyValueInstruction::new?Usage of PropertyValueInstruction::new:
§4(inter_bookmark *IBM,
    inter_symbol *prop_s, inter_symbol *owner_s, inter_pair val, inter_ti level,
    inter_error_location *eloc) {
    inter_tree_node *P = Inode::new_with_4_data_fields(IBM, PROPERTYVALUE_IST,
        /* PROP_PVAL_IFLD: */  InterSymbolsTable::id_at_bookmark(IBM, prop_s),
        /* OWNER_PVAL_IFLD: */ InterSymbolsTable::id_at_bookmark(IBM, owner_s),
        /* VAL1_PVAL_IFLD: */  InterValuePairs::to_word1(val),
        /* VAL2_PVAL_IFLD: */  InterValuePairs::to_word2(val),
        eloc, level);
    inter_error_message *E = VerifyingInter::instruction(InterBookmark::package(IBM), P);
    if (E) return E;
    NodePlacement::move_to_moving_bookmark(P, IBM);
    return NULL;
}

void PropertyValueInstruction::transpose?Usage of PropertyValueInstruction::transpose:
§1(inter_construct *IC, inter_tree_node *P,
    inter_ti *grid, inter_ti grid_extent, inter_error_message **E) {
    InterValuePairs::set(P, VAL1_PVAL_IFLD,
        InterValuePairs::transpose(InterValuePairs::get(P, VAL1_PVAL_IFLD), grid, grid_extent, E));
}

§3. Verification begins with sanity checks, but then also adds the new property value to the list of properties of the owner.

void PropertyValueInstruction::verify?Usage of PropertyValueInstruction::verify:
§1(inter_construct *IC, inter_tree_node *P,
    inter_package *owner, inter_error_message **E) {
    *E = VerifyingInter::SID_field(owner, P, PROP_PVAL_IFLD, PROPERTY_IST);
    if (*E) return;
    *E = VerifyingInter::POID_field(owner, P, OWNER_PVAL_IFLD);
    if (*E) return;
}

void PropertyValueInstruction::xref?Usage of PropertyValueInstruction::xref:
§1(inter_construct *IC, inter_tree_node *P,
    inter_error_message **E) {
    inter_symbol *prop_s = PropertyValueInstruction::property(P);
    inter_package *owner = Inode::get_package(P);
    *E = VerifyingInter::data_pair_fields(owner, P, VAL1_PVAL_IFLD, InterTypes::unchecked());
    if (*E) return;
    inter_symbol *owner_s = PropertyValueInstruction::owner(P);

    if (PropertyValueInstruction::permitted(owner_s, prop_s) == FALSE) {
        text_stream *err = Str::new();
        WRITE_TO(err, "no permission for '%S' to have this property",
            InterSymbol::identifier(owner_s));
        *E = Inode::error(P, err, InterSymbol::identifier(prop_s));
        return;
    }

    inter_node_list *FL;
    if (TypenameInstruction::is(owner_s))
        FL = TypenameInstruction::properties_list(owner_s);
    else
        FL = InstanceInstruction::properties_list(owner_s);
    inter_tree_node *X;
    LOOP_THROUGH_INTER_NODE_LIST(X, FL)
        if (PropertyValueInstruction::property(X) == prop_s) {
            *E = Inode::error(P, I"duplicate property value", NULL);
            return;
        }

    InterNodeList::add(FL, P);
}

int PropertyValueInstruction::permitted(inter_symbol *owner, inter_symbol *prop_s) {
    if (InstanceInstruction::is(owner)) {
        inter_node_list *FL = InstanceInstruction::permissions_list(owner);
        inter_tree_node *X;
        LOOP_THROUGH_INTER_NODE_LIST(X, FL)
            if (PermissionInstruction::property(X) == prop_s)
                return TRUE;
        owner = InstanceInstruction::typename(owner);
    }
    while (owner) {
        inter_node_list *FL = TypenameInstruction::permissions_list(owner);
        if (FL == NULL) internal_error("no permissions list");
        inter_tree_node *X;
        LOOP_THROUGH_INTER_NODE_LIST(X, FL)
            if (PermissionInstruction::property(X) == prop_s)
                return TRUE;
        owner = TypenameInstruction::super(owner);
    }
    return FALSE;
}

§4. Creating from textual Inter syntax.

void PropertyValueInstruction::read?Usage of PropertyValueInstruction::read:
§1(inter_construct *IC, inter_bookmark *IBM,
    inter_line_parse *ilp, inter_error_location *eloc, inter_error_message **E) {
    text_stream *prop_name = ilp->mr.exp[0], *owner_name = ilp->mr.exp[1];
    inter_symbol *prop_s = TextualInter::find_symbol(IBM, eloc, prop_name, PROPERTY_IST, E);
    if (*E) return;
    inter_symbol *owner_s = PropertyValueInstruction::parse_owner(eloc,
        InterBookmark::scope(IBM), owner_name, E);
    if (*E) return;

    inter_type val_type = InterTypes::of_symbol(prop_s);
    inter_pair val = InterValuePairs::undef();
    *E = TextualInter::parse_pair(ilp->line, eloc, IBM, val_type, ilp->mr.exp[2], &val);
    if (*E) return;

    *E = PropertyValueInstruction::new(IBM, prop_s, owner_s, val,
        (inter_ti) ilp->indent_level, eloc);
}

inter_symbol *PropertyValueInstruction::parse_owner?Usage of PropertyValueInstruction::parse_owner:
The Permission Construct - §4(inter_error_location *eloc,
    inter_symbols_table *T, text_stream *name, inter_error_message **E) {
    *E = NULL;
    inter_symbol *symb = InterSymbolsTable::symbol_from_name(T, name);
    if (symb == NULL) {
        *E = InterErrors::quoted(I"no such symbol", name, eloc);
        return NULL;
    }
    inter_tree_node *D = InterSymbol::definition(symb);
    if (D == NULL) {
        *E = InterErrors::quoted(I"undefined symbol", name, eloc);
        return NULL;
    }
    if ((Inode::isnt(D, TYPENAME_IST)) &&
        (Inode::isnt(D, INSTANCE_IST))) {
        *E = InterErrors::quoted(I"owner not an instance or enumerated type", name, eloc);
        return NULL;
    }
    return symb;
}

§5. Writing to textual Inter syntax.

void PropertyValueInstruction::write?Usage of PropertyValueInstruction::write:
§1(inter_construct *IC, OUTPUT_STREAM, inter_tree_node *P) {
    WRITE("propertyvalue ");
    TextualInter::write_symbol_from(OUT, P, PROP_PVAL_IFLD);
    WRITE(" of ");
    TextualInter::write_symbol_from(OUT, P, OWNER_PVAL_IFLD);
    WRITE(" = ");
    TextualInter::write_pair(OUT, P, PropertyValueInstruction::value(P));
}

§6. Access functions.

inter_symbol *PropertyValueInstruction::property?Usage of PropertyValueInstruction::property:
§3(inter_tree_node *P) {
    if (P == NULL) return NULL;
    if (Inode::isnt(P, PROPERTYVALUE_IST)) return NULL;
    return InterSymbolsTable::symbol_from_ID_at_node(P, PROP_PVAL_IFLD);
}

inter_symbol *PropertyValueInstruction::owner?Usage of PropertyValueInstruction::owner:
§3(inter_tree_node *P) {
    if (P == NULL) return NULL;
    if (Inode::isnt(P, PROPERTYVALUE_IST)) return NULL;
    return InterSymbolsTable::symbol_from_ID_at_node(P, OWNER_PVAL_IFLD);
}

inter_pair PropertyValueInstruction::value?Usage of PropertyValueInstruction::value:
§5(inter_tree_node *P) {
    if (P == NULL) return InterValuePairs::undef();
    if (Inode::isnt(P, PROPERTYVALUE_IST)) return InterValuePairs::undef();
    return InterValuePairs::get(P, VAL1_PVAL_IFLD);
}